Stereoselective synthesis, structure and DFT studies on fluoro- and nitro- substituted spirooxindole-pyrrolidine heterocyclic hybrids

Recent synthetic strategies of spiro-azetidin-2-one, -pyrrolidine, -indol(one) and -pyran derivatives-a review

Spiro-heterocycles have received special attention in medicinal chemistry because of their promising biological activity. Over the years, many synthetic methodologies have been established for the construction of spirocyclic compounds. Spiro heterocycles such as spiro-azetidin-2-one, -pyrrolidine, -indol(one) and -pyran derivatives have been found to exhibit diversified biological and pharmacological activity in addition to their therapeutic properties. In view of these facts, we decided in this review to present representative synthetic approaches of the aforementioned spiro heterocycles, especially in the past 20 years.

Virtual screening, molecular docking, molecular dynamics and quantum chemical studies on (2-methoxy-4-prop-2-enylphenyl) N-(2-methoxy-4-nitrophenyl) carbamate: a novel inhibitor of hepatocellular carcinoma

HDAC protein is associated with hepatocellular carcinoma. Different medicinal plants were selected for this study to analyze the inhibitory efficacy against the target protein, HDAC. Using virtual screening, we filtered out the best compounds, and molecular docking (XP) was carried out for the top compounds which filtered out. The molecular docking results showed that the title compound (2-methoxy-4-prop-2-enylphenyl) N-(2-methoxy-4-nitrophenyl) carbamate (MEMNC) has the highest docking score of about -7.7 kcal/mol against the targeted protein histone deacetylase (HDAC) compared with the other selected phytocompounds. From the molecular dynamics analysis, the RMSD and RMSF plots depicted the overall stability of the protein-ligand complex. Toxicity properties show the acceptable range of various kinds of toxicity that were predicted using the ProTox-II server. In addition, DFT quantum chemical and physicochemical properties of the MEMNC molecule were reported. Initially, the molecular structure of the MEMNC molecule was optimized and harmonic vibrational frequencies were calculated using DFT/B3LYP method with a cc-pVTZ basis set using Gaussian 09 program. The calculated vibrational wavenumber values were assigned based on Potential Energy Distribution calculations using the VEDA 4.0 program and correlated well with the previous literature values. The molecule has bioactivity as a result of intramolecular charge transfer interactions, as demonstrated by frontier molecular orbital analysis. Molecular electrostatic potential surface and Mulliken atomic charge distribution analyses validate the reactive sites of the molecule. Thus, the title compound can be used as a potential inhibitor of HDAC protein, which paves the way for designing novel drugs to treat Hepatocellular carcinoma.Communicated by Ramaswamy H. Sarma.

Targeting potential receptor molecules in non-small cell lung cancer (NSCLC) using in silico approaches

Introduction: Non-Small Cell Lung Cancer is the most prevalent type of cancer in lung cancer. Chemotherapy, radiation therapy, and other conventional cancer treatments have a low success rate. Thus, creating new medications is essential to halt the spread of lung cancer. Methods: In this study bioactive nature of lochnericine against Non-Small Cell Lung Cancer (NSCLC) was analyzed using various computational approaches such as quantum chemical calculations, molecular docking, and molecular dynamic simulation. Furthermore, the MTT assay shows the anti-proliferation activity of lochnericine. Results and Discussion: Using Frontier Molecular Orbital (FMO), the calculated band gap energy value associated with bioactive compounds and the molecule's potential bioactivity is confirmed. The H38 hydrogen atom and O1 oxygen atom in the molecule are effectively electrophilic, and potential nucleophilic attack sites were confirmed through analysis of the Molecular electrostatic potential surface. Furthermore, the electrons within the molecule were delocalized, which confers bioactivity on the title molecule and was authorized through Mulliken atomic charge distribution analysis. A molecular docking study revealed that lochnericine inhibits non-small cell lung cancer-associated targeted protein. The lead molecule and targeted protein complex were stable during molecular dynamics simulation studies till the simulation period. Further, lochnericine demonstrated remarkable anti-proliferative and apoptotic features against A549 lung cancer cells. The current investigation powerfully suggests that lochnericine is a potential candidate for lung cancer.

Multifunctional Derivatives of Spiropyrrolidine Tethered Indeno-Quinoxaline Heterocyclic Hybrids as Potent Antimicrobial, Antioxidant and Antidiabetic Agents: Design, Synthesis, In Vitro and In Silico Approaches

To combat emerging antimicrobial-resistant microbes, there is an urgent need to develop new antimicrobials with better therapeutic profiles. For this, a series of 13 new spiropyrrolidine derivatives were designed, synthesized, characterized and evaluated for their in vitro antimicrobial, antioxidant and antidiabetic potential. Antimicrobial results revealed that the designed compounds displayed good activity against clinical isolated strains, with 5d being the most potent (MIC 3.95 mM against Staphylococcus aureus ATCC 25923) compared to tetracycline (MIC 576.01 mM). The antioxidant activity was assessed by trapping DPPH, ABTS and FRAP assays. The results suggest remarkable antioxidant potential of all synthesized compounds, particularly 5c, exhibiting the strongest activity with IC₅₀ of 3.26 ± 0.32 mM (DPPH), 7.03 ± 0.07 mM (ABTS) and 3.69 ± 0.72 mM (FRAP). Tested for their α-amylase inhibitory effect, the examined analogues display a variable degree of α-amylase activity with IC₅₀ ranging between 0.55 ± 0.38 mM and 2.19 ± 0.23 mM compared to acarbose (IC₅₀ 1.19 ± 0.02 mM), with the most active compounds being 5d, followed by 5c and 5j, affording IC₅₀ of 0.55 ± 0.38 mM, 0.92 ± 0.10 mM, and 0.95 ± 0.14 mM, respectively. Preliminary structure–activity relationships revealed the importance of such substituents in enhancing the activity. Furthermore, the ADME screening test was applied to optimize the physicochemical properties and determine their drug-like characteristics. Binding interactions and stability between ligands and active residues of the investigated enzymes were confirmed through molecular docking and dynamic simulation study. These findings provided guidance for further developing leading new spiropyrrolidine scaffolds with improved dual antimicrobial and antidiabetic activities.

Expeditious entry into carbocyclic and heterocyclic spirooxindoles

Spirocyclic frameworks have attracted synthetic practitioners due to their unique three-dimensional assembly, improved metabolic stability, solubility, and increased molecular complexity with regard to planar architectures. A recent surge in the number of spirocyclic oxindoles inhibiting enzymes, moderating unique protein-protein interactions, modulating receptors and transporters is testament to their prevalence. Against this background, the construction of spirocyclic frameworks containing an oxindole moiety as a torsional switch via stereoselective methods is in great demand. Herein we present a summary of the past three years in the progress of metal, organic molecule, nanostructured particle mediated, and even uncatalyzed versions of the highly diastereo- and enantioselective pathways leading to oxindole spirocycles.